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强震区高堆石坝坝顶堆石体常由于地震加速度放大效应处于不稳定状态,目前比较经济有效的抗震措施是在坝顶一定范围内加筋来提高堆石体的强度和自稳能力。土工格栅以其与土石体相互作用的优越性而被广泛运用于土石坝坝顶抗震加固工程。以240 m高长河坝心墙堆石坝为例,分析土工格栅对强震区坝顶堆石体的抗震加固效果。运用时程法对加筋坝体进行动力反应分析,利用动力响应应力结果并结合Newmark滑块法理论,采用滑面应力分析有限元法对加筋限制高堆石坝地震永久变形的工程效果进行研究和探讨。结果表明,动力作用下格栅所受最大拉力远小于其抗拉强度,且加筋基本不影响坝体动力反应结果。可一旦坝坡发生滑移,加筋能使地震永久位移减少40%～50%,有效限制坝顶堆石体侧向滑移,提高了坝体抗震稳定性。抗震稳定性又对加筋长度与竖向加筋间距敏感,较适宜的加筋长度及间距分别为40～60 m和1～4 m。
In the strong earthquake area, the rockfill of the rockfill dam is often unstable due to the magnifying effect of earthquake acceleration. At present, more economical and effective seismic measures are to reinforce the rockfill body in a certain range to improve the strength and self-stability of the rockfill body . Geogrids are widely used in the seismic consolidation of earth-rock dam crests because of their superiority of interaction with earth and rock. Take the 240 m long river dam core rockfill dam as an example, the effect of geogrid on seismic strengthening of dam roof rockfill body in strong earthquake area is analyzed. The dynamic response of reinforced concrete dam is analyzed by using time-history method. By using the dynamic response stress results and the Newmark method, the effect of reinforced concrete with permanent deformation of the limit rockfill dam Research and discussion. The results show that the maximum tensile force of the grille under power is far less than its tensile strength, and the reinforcement does not affect the dam dynamic response basically. However, once the dam slips, the reinforcement can reduce the permanent displacement of earthquakes by 40% ~ 50%, effectively limiting the lateral slippage of the dam roof and increasing the seismic stability of the dam. The seismic stability is also sensitive to the reinforcement length and vertical reinforcement spacing. The more suitable reinforcement length and spacing are 40-60 m and 1-4 m, respectively.